Showing papers by "Spanish National Research Council published in 1978"
TL;DR: In this article, the polarization resistance method is applied to bars embedded in hardened mortar and immersed in Ca(OH)2-saturated solution, and an acceptable agreement between the gravimetric and the electrochemical weight loss data is found.
Abstract: Up to this time all the methods to measure the corrosion rate of reinforcing steels embedded in hardened concrete have been of the destructive type, which requires much time and materials and makes the full scale study of the phenomenon difficult. The authors have applied the polarization resistance method to bars embedded in hardened mortar and immersed in Ca(OH)2-saturated solution, and have found an acceptable agreement between the gravimetric and the electrochemical weight loss data.
469 citations
TL;DR: Ceil-free supernatants and in some instances, the whole bacterial culture, behaved as the pure plant hormone in improving dry weight and infection levels compared with mycorrhizal control plants.
Abstract: SUMMARY
The growth and infection levels in mycorrhizal Lavandula, Lycopersicum and Medicago plants were compared after treatment with preparations from Rhizobium, Azotobacter and phosphobacteria (a Pseudomonas). The bacterial cultures are known to contain growth substances. Ceil-free supernatants and in some instances, the whole bacterial culture, behaved as the pure plant hormone in improving dry weight and infection levels compared with mycorrhizal control plants.
117 citations
TL;DR: The inhibition of translocation by antibiotics of the neomycin, kanamycin and gentamicin groups is clearly significant for their inhibitory effect on polypeptide synthesis.
113 citations
TL;DR: In this paper, a piezoelectric transducer based on a novel vibrating stepped plate was presented for high power applications, obtaining, with a remarkable increase in efficiency and directivity, sound pressure levels in free field greater than 160 dB.
106 citations
TL;DR: Three-dimensional aspects of cells were analyzed by means of a computer program which permits neurons to be displayed as perspective views from various positions and several neuronal parameters pertaining to the length of axons and dendrites were calculated.
Abstract: The organization of area 18 in monkey has been studied in Golgi preparations. In layer III large pyramidal cells with profusely ramified basal dendritic arbors are identified. They probably represent one of the major components originating association connections. Layer II and the upper part of layer III contain cells with spine-free dendrites having axons forming long bundles descending vertically to layers IV and V. Layer IV is characterized by the presence of granular cells with local axons and small pyramidal cells with ascending recurrent axons. Layer V contains various types of pyramidal cells including giant pyramidal neurons. The mean number and distribution of dendritic spines along apical shafts were computed in four varieties of pyramidal cells. Several neuronal parameters pertaining to the length of axons and dendrites were calculated. Three-dimensional aspects of cells were analyzed by means of a computer program which permits neurons to be displayed as perspective views from various positions. Attempts were made to correlate the present description with previous observations on this and other cortical visual areas.
93 citations
TL;DR: In this article, the vapor phase isomerization of xylenes over a silica-alumina catalyst containing 4 wt% nickel has been investigated in the presence of excess hydrogen at 400 °C and pressures up to 15 atm.
72 citations
TL;DR: The use of the enzyme system superoxide dismutase for the study of the role and interactions between Mn, Cu, and Zn in the plant cell is proposed after metal determinations of the plants showed that at low concentrations of Mn in the nutrient media, copper and zinc content of leaves increased: the lower the Mn level, the higher the increase produced.
Abstract: The effect of different Mn levels on the isozyme pattern of superoxide dismutase was investigated. Pisum sativum L. plants were grown in nutrient solutions containing three Mn concentrations: 0.005 μg/ml (deficient), 0.05 μg/ml (low), and 0.5 μg/ml (optimum). Leaf extracts contained three electrophoretically distinct superoxide dismutases (SOD), two of which were inhibited by cyanide and were probably Cu-Zn-SODs, while the third one was CN-insensitive and could be either an Mn- or an Fe-SOD. At 0.005 μg/ml Mn supply the CN-insensitive SOD was significantly depressed at 15, 30, and 45 days of growth, whereas at 0.05 μg/ml Mn this isozyme was significantly decreased only at 45 days growth. The two CN-sensitive SODs were inversely related to the CN-resistant enzyme, the activities of the former enzymes being significantly increased at Mn-deficient levels throughout plant growth. Metal determinations of the plants showed that at low concentrations of Mn in the nutrient media, copper and zinc content of leaves increased: the lower the Mn level, the higher the increase produced. The CN-resistant SOD activity, as judged by its dependency on Mn, appears to be an Mn-SOD rather than an Fe-SOD. In the light of the results obtained, the use of the enzyme system superoxide dismutase for the study of the role and interactions between Mn, Cu, and Zn in the plant cell is proposed.
64 citations
61 citations
50 citations
TL;DR: In this article, a combined study using wide-angle X-ray diffraction (WAXD) and small-angle x-ray diffusion (SAXD), combined with a series of mostly low density polyethylenes with a wide range of chain defect concentrations (0.1-7%) crystallized from the melt is reported.
49 citations
TL;DR: The addition of inorganic phosphate or guanosine-5′-monophosphate to a phosphate-limited mycelial system of Streptomyces griseus inhibited candicidin production and Adenylate energy charge increased only slightly indicating that ATP is a more likely intracellular effector than energy charge in mediating phosphate control of antibiotic biosynthesis.
TL;DR: In this paper, the peroxidase/catalase ratio varied with iron supply and showed a minimum value of about 39 at 15 and 30 days growth, at adequate iron supplies.
Abstract: Pea plants (Pisum sativum L., var. Lincoln) were grown in nutrient cultures at 4 levels of iron, 0.60 ppm (low), 0.96 ppm (low), 3.0 ppm (normal) and 30 ppm (excess) for 45 days. Leaf extracts were assayed for chlorophyll, proteins, catalase and peroxidase activities. Catalase and chlorophyll were closely related to iron supply. An inverse relationship was observed between peroxidase and catalase activities. Peroxidase was increased both at dificiency and excess iron levels, but was depressed at normal iron supply. The peroxidase/catalase ratio varied with iron supply and showed a minimum value of about 39 at 15 and 30 days growth, at adequate iron supplies. Measurement of catalase activity and the use of peroxidase/catalase ratios appear to be helpful in identifying iron deficiencies in peas.
TL;DR: In this article, a new procedure based on the simultaneous solution of two eigenvalue equations is presented for calculating the half-projected Hartree-fock (HPHF) function.
Abstract: The possible uses of the half-projected Hartree–Fock (HPHF) scheme for computing potential-energy surfaces for both singlet and triplet states are investigated. For that purpose, a new procedure based on the simultaneous solution of two eigenvalue equations is presented for calculating the HPHF function. Applications are given in the cases of the singlet ground state and lowest triplet state of the lithium molecule. In both cases, the HPHF scheme is found to yield the correct general shape of the curves. The features of these curves are discussed. Finally, it is concluded that the HPHF model seems to be useful as a tool for determining potential-energy surfaces, especially in the cases of large molecules where more sophisticated methods are unmanageable.
TL;DR: Fourteen digenean trematode species, including two new species, are described from marsh and shore birds from North Columbia.
Abstract: Fourteen digenean trematode species, including two new species, are described from marsh and shore birds from North Columbia. Described as new areDrepanocephalus parvicephalus n.sp. (Echinostomatidae) andApharyngostrigea squamatoconus n.sp. (Strigeidae). Also reported areTanaisia valida (Eucotylidae),Drepanocephalus spathans, Beaverostomum brachyrhynchos, andPelmatostomum mesembrinum (Echinostomatidae),Ribeiroia ondatrae (Cathaemasiidae),Renicola cf.cruzi (Renicolidae),Galactosomum puffini, Phagicola longa, andCaiguiria anterouteria (Heterophyidae),Clinostomum complanatum (Clinostomatidae),Diplostomum compactum (Diplostomatidae), andCardiocephaloides brandesii (Strigeidae).
TL;DR: It is proposed that caffeine interferes with plant cytokinesis involving some aspect of membrane recognition and/or fusion, where calcium and magnesium are essential requirements.
01 Nov 1978
TL;DR: In this paper, four samples of NaY zeolites, cation exchanged with Ce3+ ions, have been studied in hydrated form by X-ray diffraction, showing that at low cerium concentrations the cerium cations remain in the supercage, but at high concentrations the Ce3 + ions start to occupy the smaller cages.
Abstract: Four samples of NaY zeolites, cation exchanged with Ce3+ ions, have been studied in hydrated form by X-ray diffraction. At low cerium concentrations the cerium cations remain in the supercage, but at high concentrations the Ce3+ ions start to occupy the smaller cages. The cerium occupation of site S(V) increases with increasing cerium concentrations, but above a level of 70% exchange of sodium by cerium ions, the electron density at that site decreases sharply, increasing the maxima at S(I′) and S(II).
TL;DR: It is found that the binding of either streptomycin or viomycin to 70 S ribosomes from Escherichia coli modifies the iodination of at least 5 or 9 ribosomal proteins, respectively.
01 Jun 1978
TL;DR: In this paper, a model is proposed that explains "bithorax" phenocopies as resulting from disturbances in the distribution of positional information signals for segments (inductor molecules) which compete with the product of a regulator gene (repressor) and thecis-regulatory region of the system.
Abstract: Exposure to ether of wild-type embryos of different strains ofDrosophila melanogaster causes phenocopies of different alleles of thebithorax system. Clonal analysis of the phenocopy spots has shown that the transformation caused by the treatment is maintained by cell heredity. Embryos heterozygous for several recessive mutant alleles ofbithorax show the same frequency of phenocopies as wild-type homozygous sib controls. The same holds for embryos heterozygous for the dominant mutant allelesCbx andUbx1 which are point mutants in thecis-regulatory region of the system. However, for dominant mutants which have breakpoints in this region (Ubx80,Ubx130 andHm) the frequency of phenocopies is about twice that of their sib controls. Embryos with increasing numbers of copies (from 1 to 4) of thebithorax system show a decreasing frequency of phenocopies. A model is proposed that explains “bithorax” phenocopies as resulting from disturbances in the distribution of positional information signals for segments (inductor molecules) which compete with the product of a regulator gene (repressor) and thecis-regulatory region of thebithorax system. On this model, the initiation of a metathoracic developmental pathway would result from the derepression of thebithorax system.
TL;DR: The intensity of mycorrhizal infection as affected by the interaction of differents levels of phosphate in soil and in the host was examined after a further 8 weeks.
Abstract: Non-mycorrhizal plants grown 5 weeks in a low-phosphate soil with different amounts of soluble P were transplanted to soil also with different levels of phosphate and inoculated with VA mycorrhiza. The intensity of mycorrhizal infection as affected by the interaction of differents levels of phosphate in soil and in the host was examined after a further 8 weeks. In the soil with no added phosphate mycorrhizal infection was not affected by the initial P content of the plants. When 0.8 or 1.5 g K2PO4 was given per kg soil both the external and the internal P negatively influenced the infection. In some conditions a P content that was supraoptimal for infection was not for plant growth. The critical P concentration in plants depends on the age of the host. An interaction between P and N as a factor contributing to phosphate ‘toxicity’ is discussed.
TL;DR: The results presented here support the idea that the number of genes of the insect Drosophila is of the order of 5,000 and therefore not very different from the numberof genes estimated for bacteria.
Abstract: THE number of genes in an organism is one of its fundamental biological parameters and relates to the number of functions required to construct that organism and determine its physiological characteristics. It is generally assumed that with increasing organic complexity the number of genes of the species must increase. The possibility does exist, however, that increasing complexity results from the effects of interactions between a small and relatively constant number of genes. The results presented here support the idea that the number of genes of the insect Drosophila is of the order of 5,000 and therefore not very different from the number of genes estimated for bacteria.
TL;DR: Similar results were obtained with both cell types with the most effective inhibitors being pactamycin, emetine, tubulosine, anisomycin and cycloheximide and with no significant inhibitory activity being detected with edeine complex, edEine A1, GppCH2p, polydextran sulphate, aurintricarboxylic acid, pyrocatechol violet and adrenochrome.
Abstract: A large number of compounds including actinobolin, adrenochrome, amicetin, anisomycin, aurintricarboxylic acid, blasticidin S, chartreusin, chlortetracycline, cycloheximide, doxycycline, edeine A1, edeine complex, emetine, fusidic acid, gougerotin, GppCH2p, oxytetracycline, pactamycin, polydextran sulphate, puromycin, pyrocatechol violet, sparsomycin and tubulosine have been tested for inhibitory effects on protein synthesis in cultured cells from both mouse fibroblasts (3T6 cells) and chick embryo fibroblasts (CEF). Essentially, similar results were obtained with both cell types with the most effective inhibitors being pactamycin, emetine, tubulosine, anisomycin and cycloheximide and with no significant inhibitory activity being detected with edeine complex, edeine A1, GppCH2p, polydextran sulphate, aurintricarboxylic acid, pyrocatechol violet and adrenochrome. The concentration of pactamycin required to produce 50%. inhibition of protein synthesis approximated 5×10-9M, but for most of the inhibitors it ranged from 5×10-6 M to 5×10-4 M. The molecular basis underlying these differences may be related, in addition to their intrinsic inhibitory power, to differences in permeability of the cells towards the various drugs tested. Alternatively, active accumulation of the drugs by the cells may be the variable parameter.
TL;DR: In this article, the authors performed ab initio calculations to determine the structure of azetidine and the agreement between their results and the experimental ones is quite good except for the puckering angle which has a calculated value smaller than the experimental one.
TL;DR: The effect of X-ray irradiation on hydrated and dehydrated anatase surfaces has been studied by EPR, both before and after oxygen adsorption, and a similar V-centre type defect has been found for both hydrated, irradiated TiO2, probably in the form of O3−3 as discussed by the authors.
TL;DR: A new diterpenoid with the ent -atis-16-ene skeleton, gummiferolic acid, has been obtained in very high yield (2% of the dry plant) together with the known ent -kaur- 16-en-19-oic acid.
TL;DR: Brachycarpus biunguiculatus (Lucas), un camaron nocturno that ocurre en los arrecifes of the Isla de Saint Vincent, se reporta como un nuevo limpiador de peces, y un n newvo mecanismo de limpieza is described.
Abstract: Brachycarpus biunguiculatus (Lucas), un camaron nocturno que ocurre en los arrecifes de la Isla de Saint Vincent (Antillas Menores), se reporta como un nuevo limpiador de peces. Su habitat, asociaciones, agregaciones y comportamiento de limpieza de peces, fueron estudiados. Durante el dia el camaron permanece oculto en su cueva, la cual puede estar localizada bajo corales, rocas o esponjas. Durante la noche se le encuentra activo desplazandose y limpiando peces. Con frecuencia se hallaron uno o dos individuos bajo las espinas de erizos Diadema antillarum, probablemente buscando proteccion. Los adultos permanecen solos o en parejas y los juveniles pueden encontrarse en grupos hasta de 15 individuos. B. biunguiculatus fue observado limpiando seis especies de peces, especialemente el chromis marron Chromis multilineata (Guichenot) y el pez senorita bicolor Eupomacentrus partitus (Poey), (ambos Pomacentridae). Se describe un nuevo mecanismo de limpieza.
TL;DR: The structures and absolute configurations of two new halogenated alicyclic monoterpenes isolated from the ether extract of the red alga Plocamium cartilagineum (Linn) Dixon were determined as: 1 R,2 S,4 S,5 R -5-chloro-2-E -chlorovinyl-1,4-dibromo-1 5-dimethylcyclohexane and 1 S, 2 S, 4 R,5 S -2-bromo -1- E -bromovinyl -
TL;DR: In this paper, the authors reported on results obtained from almost simultaneous observations of the differential rotation of the Ca+-chromosphere and the photospheric plasma and found a single cell with radial outflow (∼40 ms-1) extending over more than 50° in longitude.
Abstract: In this third paper of a series we report on results obtained from almost simultaneous observations of the differential rotation of the Ca+-chromosphere and the photospheric plasma. The observations (tracings of Ca+-mottles, Doppler-shift-measurements in a photospheric line) were performed at the Locarno station during two extended periods in 1976. Both data sets were used to search for a large scale circulation pattern. A regular long-lived pattern could not be detected, but a single cell with radial outflow (∼40 ms-1) extending over more than 50° in longitude has been found. Statistically significant temporal changes of the differential rotation law of the Ca+-chromosphere correlated with changes of meridional motions and differences in the rotation of the two hemispheres were observed. The data of 1976 show no significant difference in the equatorial velocity of the Ca+-chromosphere and the photosphere. A comparison of temporal variations of the rotation velocity of the Ca+-mottles and the photospheric plasma yielded no significant correlation. Finally, we correlated the measurements of the photospheric rotation performed within the equatorial belts at Locarno with those obtained at Mt. Wilson by a different method during the same periods. The Locarno data show small temporal variations (±50 m-1s) with no correlation between the two hemispheres, while from the Mt. Wilson data larger variations (±100 m s-1) with a very high correlation between the two hemispheres have been found. A comparison of both sets of data yielded no correlation at all demonstrating the need for further coordinated observations and a drastic increase of internal accuracy.
TL;DR: From the aerial parts of Sideritis chamaedryfolia six previously known ent-kaurene diterpenoids have been isolated and seven new labdane derivatives have also been obtained from the same source.
TL;DR: Une description sommaire de la mandibule gauche d'un jeune individu de Paradolichopithecus (Cercopithecine), trouvee en 1974 au gisement de La Puebla de Valverde ( Aguirre y Soto, 1974 ), est suivie d'une mise a jour des donnees fossiles de Cercophecoidea dans la sequence revisee des faunes mammaliennes du Neogene superieur europeen, d'apres les